Electric switch



May 20, 1941. H. 0. WILSON ELECTRIC SWITCH Filed Oct. 30'. 1936 INVENTOR'Herrt QWifson Patented May 20, 1941 UNITED STATES PATENT OFFICE c1.zoo-s1) llClallns- This invention relates to electric switches, and moreparticularly to switches which are electromagnetically thrown and/ormaintained in thrown condition.

The invention especially, though in certain aspects non-limitatively,contemplates devices of the class described in the form of vacuumswitches or relays. By vacuum switches or relays are meant to beincluded current-making and breaking devices of which at least theactive contacts or equivalent are enclosed in a sealed container orenvelope which is evacuated of air for well understood purposes;optionally an atmosphere of inert gas may be provided within theenvelope for one or another special purpose known in the art, withoutaltering the nature of the device as a vacuum switch (or relay) forpurposes of present consideration.

In connection with vacuum switches or relays, m invention has specialreference to those wherein a controlling magnetic field is generatedexternally of the envelope; for several practical reasonsfor example,dimculty in properly degassing relay coils or the like included withinthe envelope, envelope size, etc-such devices have been generallypreferred in the art. But limitations in performance-e. g., insensitivity and in speed, abruptness and positiveness of action havetended strongly to limit the utility of such devices; and my inventionis directed among other things to the circumvention or minimization ofthese limitations.

Thus it is an object of my invention to provide a device of the classlast described which is characterized by one or more or all of thecharacteristics of high sensitivity and speed, abruptness andpositiveness of operation.

It is a broader object to provide an electromagnetic vacuum switchsimilarly characterized.

It is another object to provide an electromagnetic vacuum relay whichmay at the same time be small, compact and highly sensitive.

It is another object to provide a generally improved electromagneticswitch.

It is another object to maintain abruptness and positiveness ofoperation at both extremities of the range of movement of the movableelements of an electromagnetic switch.

It is still another object to provide an improved magnetic circuit for amagnetic switch-i. e., one responsive to a magnetic field.

A more specific object is the tightening of effective coupling betweenan envelope-enclosed ma gnetic circuit and an external means arranged toenergize that circuit, and the provision of improved means therefor.

\ Other and allied objects will more fully appear from the followingdescription and the appended claims.

In the detailed description of my invention hereinafter set forthreference is had to the accompanying drawing, of which:

Figure 1 is a view, generally cross-sectional but principallyelevational as to components within the envelope and diagrammatic as tocertain external circuit elements, of a vacuum switch or relay embodyingmy invention;

Figure 2 is a crosssectional view taken along the line 22 of Figure 1;

Figure 3 is a partial plan view looking downwardly from the spring I1and armature l6 of Figure 1;

Figure 3a is a right-hand end view of the pole member ll of Figure 1,showing the shading ring 43 in place thereon;

' Figure 4 is a view, of similar nature to Figure 1, but illustrating amodified vacuum switch or relay embodying my invention;

Figure 5 is a partial cross-sectional view taken along the line 5-5 ofFigure 4;

Figure 6 is a view, of similar nature to Figure l, but illustrating afurther modified vacuum switch or relay embodying my invention; and

Figure 7 is a partial cross-sectional view taken along the line '|I ofFigure 6.

In Figures 1 and 2 I have illustrated a switch or relay arranged with athermal element to provide a predetermined time interval between theinception of current supply to the switch and the throwing of theswitch, and arranged with electromagnetic means for maintaining theswitch thrown during the continuance of current supply-this maintenanceby the electromagnetic means permitting the cooling of the thermalelement to re-condition the device for proper quickly-repeated operationshould that be desired. Several features of this switch cooperate toproduce a device having high sensitivity and other desirablecharacteristics; and in describing the device I shall first consider thearmature and core system, secondly the balance of the magneticstructure, and thirdly the general organization near one side thereof inmanner hereinafter more detailedly described, is supported a magneticcore system comprising two pole members II and I2 of magnetic materialsuch as iron, and for example of rectangular cross-section (transverselyof the envelope). The pole members are serially arranged andlongitudinally spaced apart to form a small gap l3 between theirmutually exposed respective ends or faces 2| and 22; it is convenienttohold them in the specified relato the bottom of each. Near the gap i3and toward the center of the device therefrom I provide a flexiblysupported armature I6 of magnetic material; this may be relatively short(1. e., longitudinally of the envelope), and o f ,a rectangularcross-section (i. e., transversely of the envelope) of the order of thatof the pole members. The flexible support of the armature is one whichpermits movement toward and away from the gap transversely of theenvelope, and

is desirably a resilient one; it may be provided by securing thearmature to the core system side of a light leaf spring I1, preferablyof non-magnetic material such as phosphor bronze or beryllium copper.This spring is conveniently ex-- tended toward the seal 2 to be clampedin the usual insulating stack or washer assembly it, which may besecured to the pole member II. The armature is biased away from the gap,as by suitable tensioning of the spring ll; but it is limitedly biased,in that its movement away from the gap is restricted (by meanshereinafter apparent) to the originally mentioned nearby position. Asystem of contacts is associated with the armature in suitable manner,such as that hereinafter set forth, to be influenced by its movement.

It will be understood that upon magnetic excitation of the core systeme.g., serial excitation of the two pole members II and l2-the armature IEwill be attracted to movement toward the gap to effectively shorten thelatter, or reduce its reluctance. I arrange the parts so that in respectof one of the pole members (e. g., l I) the movement is toward themember itself (i. e., toward its side 4|), the armature upon attractioncoming into juxtaposition-i. e., either contact or substantialcontact-with the end portion of that side. This effect is obtained byarranging the armature, in direction longitudinal of the envelope, to beco-extensive with a portion of the pole member in question, as well ofcourse as with at least a portion of the gap.

While the armature may bear a similar relationship to the other polemember, or I2, I prefer to arrange it for movement quite closely pastthe face 22 of that member rather than toward the member. the armaturethus being adapted to come into juxtaposition with that face 22. Inorder that the armature, when of the simple rectangular elevation shownin Figure 1, shall not be prevented by member II from coming into suchjuxtaposition with the face 22, I may provide the pole member l2 with anoffset I2 which has the effect of staggering the face 22 with respect to2i, to bring it nearer the center of the envelope. Preferably the degreeof this staggering will be such that the armature, when it reaches itsgap-ward movement li t of juxtaposition with a portion of the side (e.g. ll) of member II, will be in substantial alignment or juxtapositionwith the face 22 of member |2 expressed in other words, the gap-wardmovement of the armature is limited, as by member 10 tionship by a flat,non-magnetic plate I 4 secured I tively strong effective armature bias.

II, to an armature position of such substantial alignment orjuxtaposition with face 22. In Figure 1 there has of course beenillustrated the unattracted or rest position of the armature, wherein itis limitedly biased away from the gap; in this position it is out ofalignment with the face 22, preferably being in the particularrelationship of partial alignment only. It will be vunderstood that themovement of the armature transverse of the envelope is also a movementtransverse of the field across the gap, although this transverserelationship to the gap field may be somewhat oblique in view of thestaggering of the faces 2i and 22.

For producing the serial magnetic excitation of the core system a coil34 may be provided around the envelope I, so that the coil axis isparallel with and near to the pole members lll2; it will be understoodthat upon electrical excitation of the coil (as by impression of asuitable voltag across the coil leads 34a and 34b and consequent currentflow through the coil) the pole members will be serially excited in therequired manner. Particular features relating to the illustrated coil 34are hereinafter set forth.

-' I have found the armature and core system as so described to bepeculiarly satisfactory in respect of sensitivity to small excitations,and in respect of speed, abruptness and positiveness of action, both atthe beginning and ending of armature movement in response to attractionby the core system. I believe that this may result, as well as fromother causes, in large measure from at least rough equalization of thforces on the armature in the early and terminal portions of suchmovement; that this equalization tends to occur as a result of thedifferent memher-armature relationships in the respective cases of thetwo members-the force exerted on the armature by the pole member iitending to increase with armature approach to its fully attractedposition, and that exerted by the pole member l2 tending simultaneouslyto decrease; that accordingly the minimum force at any instant duringsuch movement is maintained at a relatively high value for theparticular field giving rise to the movement. As to speed, abruptnessand positiveness of armature return to the illustrated position (i. e.,in response to its bias, upon cessation of the magnetic field), the highsensitivity provides a factor favorable in any particular case to theuse of therein rela- It is also to be considered that the permissiblesmall armature size and hence mass contributes signiflcantly to thequick action.

I arrange the remainder of the magnetic system of the device to preservethe high sensitivity inherentin the armature and core system, and toheighten the overall efficiency-and in so doing I jam able to employcertain members for the joint function of improvement of the magneticsystem' and of excellent mechanical support and centralization of theelements within the envelope. These members are two spring rings I! and2! of magnetic material such as steel, each for example in the form of aleaf spring bent into the shape of the letter C (i. e., an almost closedcircle), excepting preferably for a small central flattened portion I 9aor 20a. Each of these rings." and 2. fits snugly and preferably pressesagainst the interior wall of the envelope I (excepting in its flattenedportion He or 20a).

Longitudinally they are positioned on opposite sides of the gap i3; theinterior surface of the flattened portion l3a of i3 is secured againstthe bottom or outer surface of pole member H, and the interior surfaceof the flattened portion 230 of ring 20 is secured against the bottom orouter surface of pole member II. The rings may thus form a significantmechanical support and centralizing means for the pole members or coreassembly (to which in turn other internal elements are supported throughthe insulating stack III); at the same time they approach closely to theinside of coil 34 at separated longitudinal positions-for example eitherside of the center, and intermediate the coil ,extremities and thus formefiicient means for collecting the magnetic field of the coil andpassing it through the portion of the core system which includes the gapl3.

While the rings l3 and 23 are useful with a coil 34 of simple design,they are rendered materially more effective if. employed with a coilhaving internal magnetic cylinders extending from the respective coilextremities to overlap the respective rings. -This coil structure hasbeen illustrated in the drawing. the magnetic cylinders appearing as 33and 40. These cylinders desirably fit as closely as practicable over theenvelope l; in turn they preferably fit as closely as practicable withinthe coil 34in other words, the coil 34 is formed with an internaldimension just admitting the cylinders. Thus the cylinders lie close tothe inside turns of the coil, where the internal field normally tends tvbe strongest. and therefore efilciently collect the field. They are ofcourse of such length. that an appreciable gap 33 is left between them;and this gap being of relatively higher reluctance, the field naturallyfollows the much lower reluctance circuit from either cylinder throughthe envelope to the respective collecting ring I or 20, through the coresystem across gap l3, and from the other collecting ring through theenvelope to the other cylinder.

In turn still higher efllciency may be obtained by extending the outerextremities of the cylinders 33 and 43 around the coil ends, as by theillustrated cylinder flanges 33a and 43a of magnetic material, andjoining them magnetically as by the external cylinder 31 of magneticmaterial closely fitting the outside of coil 34. This structure collectsthe external coil field and concentrates it, in its passage internallyof the coil, in the desired path above outlined. The complete coilstructure amounts to a coil encased in magnetic material excepting forthe internal annular gap 33.

It will of course be understood that in the interest of simplicity inthe drawing the coil 34 is only fractionally shown, but that it isintended for example to fill the space bounded by 33 33a--3|-43a4ll.

Attention may now be given to the general organization of the switch ofFigures 1 and-2. The spring ll will be seen to be extended away from thestack ID for a distance beyond the armature, and to have secured to itsbottom surface near its extremity a contact 33. -Below this contact 30is provided a fixed contact 3|- for example secured to the top of thepole member II. The contacts 33 and)! are normally in slight spacedrelationship, forming the normally open switch A. On the topof spring I!nearer the stack Ill-for example above the armature l8is secured acontact 32; a cooperating contact 33 is provided thereabove to form aswitch B, The contact 33 is shown carried on the bottom of a bimetallicarm 3 near one extremity thereof, the arm being clamped at its otherextremity in the insulating stack II. The bimetallic arm 3 is surroundedby a heater winding 3a, of which one extremity is electrically connectedwith contact 33 (as by connection to the arm 3) and of which the otherextremity is connected to a lug 3b clamped in the stack Ill. Thebimetallic arm 3 and contact "form the limiting means for upwardmovement of the upwardly tensioned spring I], so that switch B isnormally closed. When the arm 3 temperature is at or near ambient thedescribed normal positions, as illustrated, will be occupied by thevarious components. When the arm 31s heated, however, as by passage ofcurrent through the heater winding 3a, the arm movesdownwardly,maintaining switch B closed and forcing spring I! downwardly to closeswitch A.

Contact 3i is connected with lead-in wire 3, for example through polemember l2, plate l4, pole member II, and a lug Ila clamped against thepole member II and welded to the lead-in wire. With lead-in wire 4 isconnected spring II, and hence contacts 32 and 30. With leadin\wire 5 isconnected the lug 3b, and hence, through the heater winding 3a, thecontact 33. Thus between lead-in wires 3 and 4 lies electrically theswitch A, while between the leadin wires 4 and 5 lie electrically theserially arranged heater winding and switch B. In Figure 1 there hasbeen schematically indicated as 3 a current source. One terminal 60. ofthe source is connected with the lead-in wire 5 and with a lead 34a tocoil 34. The other terminal to of the source is connected through acontrol switch I with lead-in wire 4, while lead-in wire 3is connectedto the other coil lead 34b. Thus the heater winding 9a is connectedacross the source through the switches 1 and B, while the coil 34 isconnected across the source through the switches 1 and A.

When the control switch I is closed the heater winding 30 is energized,since switch B is normally closed; this energization heats the arm 3 andthe latter moves downwardly. After a predetermined time interval switchA will be closed, the armature l6 by that time having been moved towardbut not yet fully into the position it occupies when the magnetic systemis energized. But upon closing of switch A, switch I of course stillbeing closed, the coil 34 and hence the magnetic system are energized,attracting the armature ii to move an additional distance, and thusflexing the intermediate portion of spring i1 downwardly and openingswitch B. This opening of switch B breakes the current flow through theheater winding, so that the arm forthwith begins the process of coolingand restoration to its initial position; but the spring I! is maintaineddownwardly, and switch A' closed, by the excitation of coil 34, whichcontinues until the control switch I is opened.

The completed downward movement of any portion of the spring l'|--whichafter closing of switch I is thermally delayed and electromagneticallymaintained-may be utilized for any desired purpose and in any desiredmanner. By way of simple illustration I have shown a load 3 intended toreceive current only during the intervals of downward spring position,and have indicated the simple connection of the load in parallel withthe coil 34.

The switch so organized presents, over various combinations of devicesdirectedto a generally similar purpose, the distinct advantage ofextreme simplicity. Broadly this results, among other things, from theelectromagnetic means operating directly on the thermally responsiveswitch A itself, to take over the control of that switch from thethermal element; or, in a slightly different view, from the community ofstructure .and of response to the coil of both switches A and B.

In Figure 1, and in greater detail in the small Figures 3 and 3a, I haveillustrated an optional feature particularly for use when the fieldthrough the core system is an alternating onee. g., when the currentfrom the source 6 is alternating. This consists in the use of shadingring means of conductive material surrounding at least one of the polemembers I l and I2, or a portion thereof, near the armature IS; thefunction of such means will be understood to be the establishment in thecore system of a magnetic flux component out-of-phase with the mainflux, and accordingly effective to minimize tendencies of the armatureto vibrate. With the described arrangements, I have found a particularlyeflective position for a shading ring to be one surrounding the polemember ll,'or preferably a transverse sectional portion thereof, on theopposite side from the gap 13 of the member portion which islongitudinally co-extensive with the armature. Accordingly in thefigures in question I have shown the pole member ll provided withsymmetrically disposed longitudinal slots Ila and lib extending from oneside of the member to the other and away from the face 2i for asubstantial distance, and dividing the end portion 01' the pole intothree legs H', II" and II', and the face 2| into the three portions 2|,2|", 2I. Around the center leg H" the conductive shading ring 63, forexample of copper, is slipped to a position slightly beyond the memberportion longitudinally co-extensive with the armature, the plate l6being suitably apertured as at Ma to be secured to pole member ai'terplacement of the shading ring in its described position.

While in Figures 1 and 2 I have shown a switch thermally thrown andelectromagnetically maintained in thrown position, it will be understoodthat there is intended no limitation to such a switch of specialfeatures of my invention-such for example as the several improvements inthe magnetic system. Thus in Figures 4 and 5 I have shown, in a switcharranged to be both thrown and maintained thrown electromagnetically, amagnetic system generally similar to that of Figures 1 and 2. To show,however, that the broader described relationships of armature to coresystem are not limited to the particular arrangement of Figure 1, I haveillustrated in Figures 4 and 5 a modified arrangement wherein thoserelationships still obtain.

In Figures 4 and 5 the envelope, lead-in wires, and external magneticstructure are employed as before. Collector rings I! and. 26 are againemployed. the pole members being secured to the ring portions "a and26a. But while in the device of Figure 1 I employed staggered polemember faces and a small, elevationally rectangular armature. I haveshown in Figure 4 mutually aligned pole member faces and olisetarmature. In this figure the pole members and their respective portions,the non-magnetic polebridging member, the armature and gap have eachbeen designated with a number higher by 100 than in Figure 1; thereis nopole member offset such as 52 of Figure 1; the gap is convenientlysomewhat longer than that of Figure 1; and the armature, correspondinglylonger, is provided with an offset I53, so that there will be maintainedrelationships oi armature to upper side (e. g., l6!) of the one pole,and of armature to face (e. g., 122) of the other pole, similar to thecorresponding relationships in Figure 1. y

In either of the arrangements of Figures 1 and 4 that pole member with aside portion of which the armature is longitudinally co-extensive mayconveniently form a stop for gap-ward movement of the armature. It isnot imperative, however, that the juxtaposition with this side portioninto which the armature is attracted be one of intimate contact; and ifdesired the coming into such intimate contact may be positively obviatedas by a thin piece of non-magnetic material interposed between armatureand pole sideshown for example in Figure 4 as the thin piece I56 securedto the bottom of the portion of armature H6 which would otherwise comefully into contact with pole side I.

By way of further typical differences from earlier figures, a modifiedcontact arrangement is shown in Figures 4 and 5. The armature is showncarried on the bottom of a spring 1, similar to spring l1 of Figure 1but not necessarily extended so far beyond the armature, and in thisinstance connected to lead-in wire 3. On top of the spring H1, forexample immediately opposite the armature, is secured a contact 26. Tolead-in wire 6 is electrically connected a rod or strip 23, which ispreferably of non-magnetic material but may if desired be somewhatresilient; this is clamped in stack Hi and extends therefrom abovespring H1 to a position opposite the contact 26. To this strip 23 atthis position is'secured a contact 21, against which contact 26 may bearwhen the armature I6 is unattracted and spring 1 obeys its bias; thestrip 22 and contact 21 may thus form the means for restricting movementof the armature away from the gap. To lead-in wire 6 may be electricallyconnected a leaf spring 26, preferably of non-magnetic material, whichis clamped in stack l6 and extends above strip 23 to opposite theextremity of spring 1. A rod or spacer 25 of insulating material issecured to this spring 26 near its extremity to extend therefrom intoabutment against spring H1 near its extremity; the spring 26 is lightlytensioned oppositely to spring ll1-i. e., the two are tensioned towardeach otherAo that the two spr'ngs move in unison, and normally t'ieeilective bias on the armature I6 is the relatively more powerful upwardspring H1 bias minus the relatively les powerful downward spring 26bias. To the strip 22, for example above contact 21, is secured anothercontact 26, and to the spring 26 above the contact 26 another contact29; the mutual spacing of contacts 26 and 26 is such that uponattraction of the armature to gap-ward movement these two contacts willtouch each other just before that movement is completed. Contacts 26 and21 may be considered as forming a normally closed switch section 0connected across lead-in wires 3 and 6, and

contacts 26 and 26 as forming a normally open switch section D connectedacross lead-in wires 6 and I.

A purely typical circuit is illustrated in connection with the device ofFigure 4. The current source 6 has been shown connected to a load lcthrou h the switch section and to a load Id through the switch sectionD, the two switch sections being portions of a single-pole, double throwswitch of which lead-in wire 4 represents the pole and lead-in wires 3and I the respective throw contacts; the coil 34 is connected to thecurrent source through the control switch I. When the switch I is closedthe core system is magnetically energized and the armature H6 isattracted into juxtaposition with the top side Ill of pole member I andwith the end face I22 of the pole member H2, opening the switch sectionC and closing the switch section D (this amounting to a throwing of theentire single-pole, double-throw switch). The thrown positions will ofcourse be maintained as a result of the continued magnetic energizationof the core system until opening of switch I. By reason of thetendencies toward equalization of forces throughout armature movement,and of other characteristics of the improved armature-core systemrelationships above discussed, both the opening of switch C and closingof switch D (in early and terminal Portions of the armature movement,respectively) occur rapidly, abruptly and positively.

In Figures 6-7 I show a device and system similar to that of Figure 1,excepting that there is employed therein an armature which, instead ofhaving difierent relationships to the two respective pole members,may'have similar relationships to the twoe. g., may be arranged formovement into juxtaposition with portions of the top sides of both polemembers. The armature, gap and two pole members have been indicated as2l6, 2l3, 2|l-2I2 respectively. The pole member 2| l, secure with thestack l0 and the ring portion Ila, may be formed with an oiIset l towardthe armature; the pole member 2l2, secure with the ring portion 20b, maybe formed with the like offset 252. The mutually exposed end faces 22iand 222 of the pole members may be aligned with each other and separatedby the gap 2"; a non-magnetic plate 2 may bridge the gap, secured toboth po e members. In a longitudinal direction the armature 2l6, carriedby the spring ll, may be centralized over the gap; but in this case thearmature extends not only over the gap but also to some extent overportions of the top sides (2 and 242) of both the pole members. Normallythe armature is limitedly biased away (mm the gap as before; but it isnow adapted to be moved by arm 9 toward a position of juxtaposition withportions of the sides (24!, 242) of both the pole.

heated by an electric current-this is not essential for certainpurposes. Thus the heater winding in and connections thereto may beomitted, or equivalently the switch I (shown in series with lead-in wire5 in Figure 6) opened; the system will then function, assuming switch Iclosed, to close switch A and keep it closed when and after the thermalelement (e. g., bimetallic arm 9) has been heated to a predeterminedtemperature by any means, such as ambient temperature.

While I have illustrated and described my invention in terms ofparticular embodiments thereof, it is to be understood that I intend nounnecessary limitations by virtue of the details of those embodiments,which may obviously be varied within wide limits without departure fromthe spirit of my invention; rather I intend to express the scope of theinvention in the following claims, as broadly as the state of the artwill permit. No claims, however, are made herein to the arrangements ofthe switch contacts to form switches A and B or C and D, or to theconnectiors of those switches or to their operation or their functions,including the operation of thermally throwing and electromagneticmaintaining one or more of themthis and allied subject matter havingbeen disclosed and claimed in my copending application Serial No.325,935, filed March 26th, 1940, as a division of the instantapplication.

I claim:

1. A magnetic switch system having two pole members arranged with a gaptherebetween for serial magnetic excitation; and a switch-influencingarmature supported near said gap for movement transverse of the gapfield toward one said member, and 'co-extensive normally to saidmovement with portions of said gap and of said one member only.

2. A magnetic switch system having two pole members arranged for serialmagnetic excitation, the faces of the respective said members nearesteach other forming a gap; and a switch-influencing armature supportedfor movement into juxtaposition with the side of a first said member andwith said face of the second member, and limitedly biased away from saidposition.

3. A magnetic switch system having two pole members arranged for serialmagnetic excitation, the faces of the respective said members nearesteach other being staggered and forming a gap; and a switch-influencingarmature supported for movement into juxtaposition with the side of afirst said member and with said face of the second member, and limitedlybiased away from said position.

4. A magnetic switch system having two pole members arranged for serialmagnetic excitation, the faces of the respective said members nearesteach other forming a gap; a switch-influencing armature supported formovement toward the side of a first said member and past said face ofthe second member; and means for restricting said armature movement to aposition of substantial alignment with said second member face.

5. A magnetic switch system having two pole members arranged for serialmagnetic excitation, the faces of the respective said members nearesteach other forming a gap; and a switch-influencing armature supportedfor movement toward the side of a first said member and past said faceof the second member, said first member forming a means for restrictingsaid movement to an armature position of substantial alignment with saidsecond member face.

6. A magnetic switch system having two pole members arranged for serialmagnetic excitation, the taces of the respective said members nearesteach other forming a gap; and a switch-infiuenc ing armature supportedin spaced relation to the side of a first said member only and out ofalignment with said face of the second member, and movabletowardsaid'first member side and simultaneously into substantial alignmentwith said second member face.

'7. A magnetic switch system having two pole members arranged for serialmagnetic excitation, the faces of the respective said members nearesteach other forming a gap; and a switch-influencing armature supported inspaced relation to the side of a first said member only and in partialalignment only with said race of the second member, and movable towardsaid first member side and simultaneously into substantial alignmentwith said second member face.

8. In a switch system including an evacuated envelope: a magneticallyinfluenced switch including mutually spaced pole members within saidenvelope, and resilient field collectors respectively associated withsaid pole members and resiliently fitting against the internal wall ofsaid envelope.

9. In a switch system including an evacuated envelope: a magneticallyinfluenced switch including mutually spaced pole members within saidenvelope, and thin, substantially cylindrical field collectorsrespectively associated with said pole members and substantially fittingagainst the internal wall of said envelope.

10. In a switch system including an evacuated envelope: a switch and amagnetic circuit innuencing said switch, within said envelope; mutuallyspaced internal field collectors forming terminals of said internalmagnetic circuit and positioned adjacent the interior wall or saidenvelope; external field collecting cylinders of magnetic materialsurrounding said envelope opposite said internal collectorsrespectively; and a coil surrounding said external field collectingcylinders.

11. In a switch system including an evacuated envelope: a switch and amagnetic circuit influencing said switch, within said envelope; mutuallyspaced internal field collectors forming terminals oi said internalmagnetic circuit and positioned adjacent the interior wall of saidenvelope:

external field collecting cylinders of magnetic.

material surrounding said envelope opposite said internal collectorsrespectively; a coil surrounding said external field collectingcylinders; and means substantially joining said collecting cylindersmagnetically around said coil.

HERBERT 0. WILSON.

